Foundations PDF

Building and Furniture Technology PRESENTED BY: D.A. GILROY  Text for Today John 14:1-3  Let not your heart be troubled, he believe in God believe also in me; in my father’s house are many mansions, if it were not so I would have told you, I go to prepare a place for you and if I...

Building and Furniture Technology PRESENTED BY: D.A. GILROY  Text for Today John 14:1-3  Let not your heart be troubled, he believe in God believe also in me; in my father’s house are many mansions, if it were not so I would have told you, I go to prepare a place for you and if I go to prepare a place I will come again and receive you unto myself that where I am there he may be also. TOPIC : FOUNDATIONS  Objectives  State what is a Foundation  Identify different types of Foundation  State the purpose of a Foundation  Draw a typical Foundation  FOUNDATIONS  The Foundation is that part of the structure in direct contact with and transmitting loads to the ground. FUNCTIONS OF A FOUNDATION  Provides stability for the structure  Transfers loads evenly from the building to the supporting soil FUNCTIONS OF A FOUNDATION  Protect against damage due to shrinkage of soil  Provides a base for the building  FACTORS TO CONSIDER  Weight of the building - 1 storey or 2 storey building - type of roofing  Soil Type -Bearing capacity- sandy soil (strongest soil type), clay soil (weakest)  TYPES OF FOUNDATIONS  Shallow Foundation  Deep Foundation  Pile Foundation  Strip Foundation  Raft Foundation  SHALLOW FOUNDATIONS A shallow foundation is a type of building foundation that transfers building loads to the earth very near to the surface.  TYPES OF SHALLOW FOUNDATIONS  Pad Foundation  Strip Foundation  Raft Foundation  Stepped Foundation PAD FOUNDATIONS  PAD FOUNDATIONS  Pad foundations are used to support an individual point load such as that from a column. They may be circular, square or rectangular. PAD FOUNDATIONS STRIP FOUNDATION  STRIP FOUNDATIONS  Strip foundations are used to support a line of loads, either due to a load-bearing wall, or if a line of columns need supporting. STRIP FOUNDATION (SECTIONAL VIEW) STRIP FOUNDATION (PICTORIAL VIEW) RAFT FOUNDATION  RAFT FOUNDATIONS  Raft foundations are a good solution if the soil has a poor bearing capacity. It is used to spread the load from a structure over a large area, normally the entire area of the structure. The raft foundation also forms the ground floor of the building. (clay soil)  Mostly used in clay soil , RAFT FOUNDATION STEPPED FOUNDATION  STEPPED FOUNDATIONS  Stepped foundations are built on sloping sites. They are constructed in a series of steps. STEPPED FOUNDATION  DEEP FOUNDATIONS A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation  PILES  Pile foundations are relatively long, slender members that transmit foundation loads through soil having low bearing capacity to deeper soil or rock having a high bearing capacity.  Mostly used on bridges PILE FOUNDATION  PARTS OF A TYPICAL PILE Piles are made up of certain basic parts. The main parts of a typical pile are:  Head: The upper part of the pile in final position.  Foot: The lower part of the pile in final position.  PARTS OF A TYPICAL PILE CONTD.  Tip: The small end before or after it is placed in position.  But: The large end before or after it is placed in position.  Pile Ring: A wrought iron or steel hoop that is placed on the head of the pile to prevent cracking or splitting.  PARTS OF A TYPICAL PILE CONTD.  Driving head: A device placed on the head of a pile to receive hammer blows and to protect it from injury while it is being driven.  Pile Shoe: A metal cone placed on the tip of a pile to protect it from cracking or splitting. PARTS OF A TYPICAL PILE CONTD. TYPES OF PILE CONCRETE PILES TYPES OF PILES CONTINUED  Concrete Piles  There are two main types of concrete piles. These are the cast-in place and the precast.  The Cast-in place pile is formed in the ground, in the position in which it is to be used. TYPES OF PILES CONTINUED  The Precast is usually cast in factory where pre-stressing techniques can be employed. After curing, it is driven or jetted like a wood pile. STEEL PILES  TYPES OF PILES CONTINUED  Steel Piles  A steel pile may be a rolled H section or a steel pipe known as a tabular pile. Due to their small cross section, steel piles can often be driven into dense soils where driving a pile of solid cross section through dense soil would be difficult. PILE DRIVING MACHINE PILES UNDER A BRIDGE What have you learnt Today?  The Quiz 1. What is Foundation? 2. List three (3) types of shallow foundation 3. What is Deep foundation? 4. What is the purpose of foundation IDENTIFY THE FOUNDATION  ANSWER  STRIP FOUNDATION IDENTIFY THE FOUNDATION  ANSWER  PAD FOUNDATION IDENTIFY THE FOUNDATION  ANSWER  RAFT FOUNDATION